KEY POINTS:
Police are refusing to say which cases - if any - have been solved by rewards being offered, though the amount put up for information in the past five years is now more than $400,000.
The latest reward to be offered - worth $75,000 - relates to the murder of Japanese tourist Kayo Matsuzawa whose body was found in a cupboard in the Centrecourt building in central Auckland in 1998.
Police offered $50,000 for information in 1998 and despite evidence being gathered there was no prosecution.
New Zealand Law Society criminal law committee convenor Jonathan Krebs said police sometimes offer rewards in when they reach a stalemate.
He said detectives can then get a new lead and take the investigation in a direction they may not have otherwise explored.
The reward offered in the Kayo Matsuzawa case is the eleventh cash reward to be offered in the past five years, bringing the total to $405,000.
But police would not provide information on whether or not offering rewards was an effective way of getting information.
An Official Information Act request by the nzherald.co.nz was sent to the New Zealand Police asking how many rewards had been claimed and how much police had paid out in the past five years.
The police declined to answer the question.
In reply to the nzherald.co.nz for information, Detective Senior Sergeant McGill said the number of rewards paid out and the amount of money could not be disclosed because of "confidentiality clauses contained in every reward payment agreement".
Mr McGill also declined to name the cases that had been solved due to information coming to police after a reward had been offered.
He did provide a brief description of the cases in the last five years where rewards have been offered.
A complaint has been sent to the Ombudsman by nzherald.co.nz concerning the police's response, and the fact that the reply arrived more than one month later than the statutory time frame.
Mr McGill said information received after a reward is offered is not tainted. He said all information is assessed.
"Part of that assessment includes a determination as to whether the information is reliable, relevant, and credible and can be corroborated," Mr McGill said.
He said if the information meets the required standard then it is a matter for a jury to assess it.
Mr Krebs, who has been involved in a case where a reward was used to get information, said there is nothing wrong with offering rewards.
"Sometimes the information results in no prosecution. What is being rewarded is not the material itself but the person coming forward," Mr Krebs said.
He said the courts would come down hard on anyone who gave information for money that was later found to be false, but that has never happened to the best of his knowledge.
REWARDS
$15,000 reward offered for information leading to the conviction of a person responsible for the arson of a house in Prembleton, Christchurch in 2002. The reward was a joint offer by police and Farmers Mutual Group. In force until March 2003.
$20,000 reward offered for the apprehension of Joe Tua Coleman who was wanted in connection with the murder of George Matahaere in force until February 2003.
$20,000 for evidence or information that leads to the location of Sara Louise Neithe or her body and the conviction of any person responsible and information that results to the location of her car. In force until December 2003. The reward was offered again after no one came forward, this time with an offer of $50,000.
$5,000 reward offered for material information or evidence that leads to the apprehension of Michael Joseph Cavanagh and Shannon Kay Stevens. In force until July, 2004.
$20,000 reward offered for information in relation to finding two offenders for the alleged attempted murder and sexual violation of a 14 year-old girl. In force until September 2005.
$50,000 reward offered in relation to the disappearance of Margaret Kaye Stewart who went missing in June, 2005 in the Rimutaka Forest Park in Wainuiomata. In force until July 13, 2007.
$50,000 reward offered in relation to the disappearance of Nicholas Pike who was last seen alive in March 2002 in Mt Mauganui. In force until July, 2007.
$50,000 reward offered in relation to the death of Katrina Jeffries whose body was found in July 2005 in the Waikowhai Reserve in West Auckland. In force until December 31, 2007.
$50,000 reward offered in relation to the disappearance of Grant Trevor Adams who was last seen alive in Tauranga in November, 2005. Offer in force until December 31, 2007. Police have made an arrest in relation to Mr Adams' death. At the time police said the reward was not claimed.
